The overall objectives of this research are to understand the physiology of bacterial conjugation by continuing our exploration of the events proceeding in the donor and in the zygote. In the donor, events leading to conjugation appear to be determined by the sex factor; hence, genetic and enzymatic analyses of this episome are together one of the main activities to be continued. In the zygote, recombination and repliconation are the two major processes of inheritance; hence, genetic and enzymatic analyses of these processes will also be continued. In addition, certain related objectives may also be pursued. The hypothesized involvement of recombination in many particular phenomena of bacterial genetics gives a clue to the possible importance of this process for determining the response of bacteria to their environment. For example, repair of lesions in DNA produced by ultraviolet irradiation or treatment with alkylating agents and induction of prophage lambda may occur through the action of enzymes or proteins involved in recombination. The biological generality of our findings can be assessed through extension of our studies to include a bacterial species other than E. coli. We have chosen the common pathogen Pseudomonas aeruginosa because of the occurrence of conjugation transduction and lysogeny in this species.